Try for the third time to teach getFirstTerminator() about debug values.

This time let's rephrase to trick gcc-4.3 into not miscompiling.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123432 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 11 insertions, 4 deletions

diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp
index ad1ab28..95b8f86 100644
--- a/lib/CodeGen/MachineBasicBlock.cpp
+++ b/lib/CodeGen/MachineBasicBlock.cpp
@@ -156,9 +156,10 @@ MachineBasicBlock::SkipPHIsAndLabels(MachineBasicBlock::iterator I) {
 
 MachineBasicBlock::iterator MachineBasicBlock::getFirstTerminator() {
   iterator I = end();
-  while (I != begin() && (--I)->getDesc().isTerminator())
+  while (I != begin() && ((--I)->getDesc().isTerminator() || I->isDebugValue()))
     ; /*noop */
-  if (I != end() && !I->getDesc().isTerminator()) ++I;
+  while (I != end() && !I->getDesc().isTerminator())
+    ++I;
   return I;
 }
 
diff --git a/lib/CodeGen/PHIElimination.cpp b/lib/CodeGen/PHIElimination.cpp
index 923fa21..b940e26 100644
--- a/lib/CodeGen/PHIElimination.cpp
+++ b/lib/CodeGen/PHIElimination.cpp
@@ -339,6 +339,8 @@ void PHIElimination::LowerAtomicPHINode(
 #ifndef NDEBUG
         for (MachineBasicBlock::iterator TI = llvm::next(Term);
              TI != opBlock.end(); ++TI) {
+          if (TI->isDebugValue())
+            continue;
           assert(!TI->readsRegister(SrcReg) &&
                  "Terminator instructions cannot use virtual registers unless"
                  "they are the first terminator in a block!");
@@ -347,9 +349,13 @@ void PHIElimination::LowerAtomicPHINode(
       } else if (reusedIncoming || !IncomingReg) {
         // We may have to rewind a bit if we didn't insert a copy this time.
         KillInst = Term;
-        while (KillInst != opBlock.begin())
-          if ((--KillInst)->readsRegister(SrcReg))
+        while (KillInst != opBlock.begin()) {
+          --KillInst;
+          if (KillInst->isDebugValue())
+            continue;
+          if (KillInst->readsRegister(SrcReg))
             break;
+        }
       } else {
         // We just inserted this copy.
         KillInst = prior(InsertPos);